Users who look up the term "Zerg rush" Friday are finding the latest in a series of geeky Easter eggs planted by the search giant's engineers. The search produces a swarm of marauding "O's" which inevitably destroy virtually everything on the search-results page.

The term quickly became a top search topic for Google Friday morning, as gamers and the merely curious flocked to the feature.

In gaming terms, a "Zerg rush" is when a player is swarmed by a huge number of weak opponents. Any one of the bad guys is easy to take out, but the threat is that they'll overwhelm you with sheer numbers.

It came from "Starcraft," a 1998 real-time strategy game in which a player could choose to play as "Zergs," an alien race. Skilled players soon learned that they could quickly spawn a massive number of low-level units ("zerglings") and overwhelm their opponents.

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According to Know Your Meme, the first instance of the term came during a game among some Korean players (a significant portion of the early "Starcraft" player base). The first Urban Dictionary definition of the term appeared in 2004.

Since then, the use has expanded. In some multi-player games, "zerging" has come to refer to a gamer who, often against the game's rules, creates multiple accounts to get an unfair advantage over other players.

It has come to be used in some circles as slang for any situation in which someone is overwhelmed by superior numbers.

In the Google search, the "O's" from the Google logo turn into "attackers" which multiply and begin banging themselves against text on the page. Users can click to "kill" them, but will eventually fall to the rush.

After they take out your results, the O's band together to spell out "GG" -- gaming slang for "good game." If a player does well enough, they can post their score to Google+.

Google, which famously encourages employees to take on sometimes-silly side projects in the course of their work weeks, has long been known for implementing winks and nods into their products. Most notably, "Google Doodles" transform the search page's iconic logo into other (sometimes animated) images to celebrate special days.

It's hard to know when these "eggs" get planted at Google headquarters. But in recent months, more and more have been discovered.

Currently, Googling "askew" or "tilt" will knock the search-results page slightly off-kilter and "do a barrel roll" will make the results page ... well ... do a barrel roll. Meanwhile, a search for "chuck norris google" renders this entry in the litany of one-liners about the action star: "Google won't search for Chuck Norris because it knows you don't find Chuck Norris, he finds you."